The present invention is directed to composites useful in electrostatographic, including electrophotographic, image on image, contact electrostatic printing, digital and the like processes. The invention further relates to thin composite coatings, wherein the coating is a perfluoropolymer, and in embodiments, a perfluoroelastomer. The composites can be used in a variety of applications in the electrostatographic or electrophotographic fields.
In a typical electrostatographic reproducing apparatus such as electrophotographic imaging system utilizing a photoreceptor, a light image of an original to be copied is recorded in the form of an electrostatic latent image upon a photosensitive member and the latent image is subsequently rendered visible by the application of electroscopic thermoplastic resin particles which are commonly referred to as toner. Generally, the electrostatic latent image is developed by bringing a developer mixture into contact therewith. Toner particles are attracted from the carrier granules to the latent image forming a toner powder image thereon. Alternatively, a liquid developer material may be employed. After the toner particles have been deposited on the photoconductive surface, in image configuration, the developed image is transferred to a receiving copy substrate. The image is subsequently fused to a copy substrate by the application of heat in combination with pressure.
Many of the components useful in the electrostatographic and electrophotographic processes require low surface energy materials for releasing both powder and liquid toner. Other requirements for coatings for many of the components are that the material coatings have superior release, wear and temperature resistance. Known component coatings include rigid fluoropolymers such as tetrafluoroethylene, perfluoroalkoxy, and polytetrafluoroethylene polymers. These rigid fluoropolymer materials demonstrate adequate release and wear properties, and are temperature resistant. However, these fluoro-materials are not adequate when high copy quality is required or when smooth copy substrates are used. The release properties tend to decrease with time and heavy use of the component. Further, adhesion problems have occurred with the rigid fluoropolymer coatings causing the coating to delaminate or pull apart from the component.
A more conformable coating possesses improved release characteristics over the rigid fluoropolymer materials. Many conformable coatings such as silicone and fluoroelastomers such as VITON(copyright) (a fluoro-tetrapolymer from DuPont) provide good electrical, thermal and mechanical properties. Further, conformable materials such as VITON(copyright) have a higher surface energy (for example, from about 34 to about 37 dynes/cm) than that of silicone (for example, from about 21 to about 25 dynes/cm). The higher surface energy can result in inferior toner release. Lower surface energy conformable coatings such as silicone materials may have better release properties, but tend to swell in the presence of oils, such as fusing oils or release agents, and especially hydrocarbon fluids.
Conformable fluoroelastomer materials such as conformable perfluoroelastomers have been developed and used as outer coatings in some electrostatic components such as fuser rollers and transfer rollers. These materials have the superior release properties, as well as superior mechanical, electrical and thermal properties. In addition, conformable perfluoroelastomers do not tend to swell in the presence of oils.
U.S. Pat. No. 4,610,918 teaches a composite having a perfluoropolymer initial layer thereon.
U.S. Pat. No. 4,654,235 discloses a composite having a perfluoroelastomer layer and outer layer positioned on the perfluoroelastomer layer.
U.S. Pat. No. 4,770,927 discloses a composite having a perfluoroelastomer layer and outer layer positioned on the perfluoroelastomer layer.
U.S. Pat. No. 4,894,686 discloses a transfer roller which may be coated with a perfluoroelastomer.
U.S. Pat. No. 5,230,937 discloses a composite having a perfluoroelastomer layer and outer layer positioned on the perfluoroelastomer layer.
U.S. Pat. Nos. 5,614,933 and 5,502,476 teach an ink jet heated drum having a perfluoroelastomer layer thereon.
U.S. Pat. No. 5,572,275 discloses a fixing device having a mixture layer prepared by mixing a perfluoroelastomer having rubber elasticity and a fluorine resin.
U.S. Pat. No. 5,759,329 teaches a tube or pipe having an inner layer of a perfluoroalkoxy ethylene polymer.
U.S. Pat. No. 5,777,650 discloses an ink jet printer having a transfer roller, wherein the transfer roller may have a perfluoroelastomer layer thereon.
However, conformable fluoroelastomers can be very expensive. For example, KALREZ(copyright) (available from DuPont) costs approximately $1,000.00 per pound. In addition, conformable perfluoroelastomers have had problems with adhesion, and have exhibited delamination of the outer layer from the component substrate.
It is desired to develop a conformable coating with superior electrical properties, temperature stability, and improved release properties, which does not swell in the presence of oils. In addition, it is desired to develop a conformable coating which has superior adhesion properties and which has a decreased tendency to delaminate. Moreover, it is desired that the conformable coating be cost effective.
Embodiments of the present invention include: an electrostatographic component comprising a substrate and an outer coating of a thin, conformable perfluoroelastomer, wherein the outer coating has a thickness of from about 1 to about 75 micrometers.
Embodiments further include: an image forming apparatus for forming images on a recording medium comprising a processing station, wherein the processing station comprises a xerographic system member comprising a substrate and an outer coating of a thin, conformable perfluoroelastomer, wherein the outer coating has a thickness of from about 1 to about 75 micrometers.
In addition, embodiments include: an image forming apparatus for forming images on a recording medium comprising a processing station, wherein the processing station comprises a xerographic system member comprising a substrate and an outer coating of a thin, conformable perfluoroelastomer, wherein the outer coating has a thickness of from about 1 to about 75 micrometers, and wherein the perfluoroelastomer is the reaction product of perfluoro(3-phenoxypropylvinyl ether) and at least one fluorine-containing ethylenically unsaturated monomer.